Bug 126663

Summary: Subpixel layout: SliderThumbElement value needs flooring.
Product: WebKit Reporter: zalan <zalan>
Component: Layout and RenderingAssignee: zalan <zalan>
Status: RESOLVED INVALID    
Severity: Normal CC: jonlee, simon.fraser, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on:    
Bug Blocks: 126283    

Description zalan 2014-01-08 13:45:16 PST 
While calculating the thumb value at SliderThumbElement::setPositionFromPoint() as the result of a (touch) event, the subpixel on result is off by one.

position = offset.y() - (renderBox()->height() / 2) - trackBoundingBox.y() - renderBox()->marginBottom();

This is similar to bug 126658

failed case:
fast/forms/range/slider-transformed.html
fast/forms/range/slider-zoomed.html
Comment 1 Simon Fraser (smfr) 2014-01-08 15:29:43 PST 
Prefer new behavior.
Comment 2 Radar WebKit Bug Importer 2014-01-14 10:24:15 PST 
<rdar://problem/15815554>